創新型LED全晶圓含透鏡封裝製程及微結構複合透鏡模具製作探討

Development of LED Wafer-level Packaging Process and Micro-structure Hybrid Lens Mold

林上評(Shang-Ping Lin)

指導教授 ： 楊申語

國立臺灣大學/工學院/機械工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.01864

摘要

LED現今已廣泛應用於照明、顯示器等，但LED封裝製程，仍主要是各別獨立封裝，產能低，成本相對高，發展高效率的封裝技術成為重要議題。近年來，為提高生產效率，在晶圓上封裝，並同時完成光學鏡片製作，是目前LED封裝研究的目標。本研究以轉注成型(Transfer Molding) 及紫外光固化(UV curing)兩種技術，進行LED全晶圓含透鏡封裝製程研究。
本研究首先設計組裝轉注成型機台，以轉注成型製程進行LED全晶圓含透鏡封裝實驗，根據製程需求，選擇封裝膠體，並針對膠體量、合模壓力、模具溫度、進膠氣壓之製程參數作探討，成功在4吋晶圓上製作8 × 8顆透鏡封裝，成型透鏡之高度轉寫皆達96 %以上，並在模具溫度100 ℃、進膠氣壓20 psi情況下，有最佳高度轉寫率97.7 %。
為縮短製程時間、降低製程溫度，本研究並使用氣體輔助壓印UV固化製程，進行LED全晶圓含透鏡封裝實驗。首先製作具透光性PDMS模具，使用自組裝刮刀機台將紫外光固化樹脂封裝膠體塗佈於模具上，探討PDMS透鏡模具在氣體壓力下，透鏡變形情形，和不同進氣壓力下，透鏡高度轉寫率及均勻度。在進氣壓力10、15psi情形下，模具均勻受壓，透鏡轉寫均勻度高、透鏡高度轉寫率約為98%。
由於不同透鏡外型有不同的光學性質，本研究以光學模擬探討微透鏡陣列複合透鏡與V型溝槽結構複合透鏡光學性質。本研究並以二次氣輔熱壓翻製及PDMS澆鑄製作有微結構透鏡之模具，並使用氣體輔助壓印UV固化製程，成功在4吋晶圓上製作8 × 8顆微結構透鏡封裝。

關鍵字

LED晶圓級封裝 ； 轉注成型 ； 紫外光固化 ； 氣體輔助壓印成型 ； 微結構複合透鏡

並列摘要

LED has been widely used in illumination and display. However, most LEDs are packaged by dispensing method, which is low in productivity and complicated in process. Developing an efficient packaging technology has become an important issue. Wafer level packaging integrated with lens has drawn great research effort. In this study, transfer molding technique and gas-assisted imprinting UV curing process are employed to perform the wafer level packaging.
First, a transfer molding machine was designed and implemented for wafer-level LED packaging integrated with lens. The effects of resin volume, mold temperature, clamping force and injection pressure on lens formability were investigated. 8 × 8 packaging with lens has been successfully realized on a 4-inch wafer. The replication rate of lens’ height is more than 96%. With temperature of 100 ℃ and injection pressure of 20 psi, the 97.7% replication rate of lens height can be reached.
The gas-assisted UV curing process for wafer-level LED lens packaging was also developed. The UV transparent mold was fabricated with gas-assisted hot embossing and PDMS casting. The reversal imprinting process was used for bubble free. The effects of forming parameters including imprinting pressure, size of PDMS mold, UV resin coating time on lens formability were investigated. An 8×8 packaging with integrated lens structure on 4-inch wafer had been successfully realized. Homogeneous lens shape with a 98% replication rate of lens’ height can be reached.
Since lens’ shape affects optical performance, this study further investigated the effects of microstructures on lens surface with simulation. The optical performances of micro-lens hybrid lens and V-cut structure hybrid lens were analyzed and confirmed. The molds for the micro-structured hybrid lens were manufactured by 2-step gas-assisted hot embossing and PDMS casting. Using the micro-structured hybrid mold and the gas-assisted imprinting UV curing process, wafer level packaging integrated with micro-structured hybrid lens has been successfully realized. This study demonstrates the potential of the gas-assisted imprinting UV curing process and micro-structured hybrid lens in LED wafer level packaging.

並列關鍵字

LED wafer-level packaging ； Transfer Molding ； UV curing ； gas-assisted hot embossing ； micro-structured hybrid lens

參考文獻

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